The Phoronida, a probable close relative of
the Brachiopoda, is the outgroup on the above cladogram. Both groups belong
to the larger group Lophophorata.

Traditionally, the brachiopods have been split into
two major groups, the Inarticulata and the Articulata.
The Inarticulata got their name from the fact that they
possess two valves that do not have an articulating hinge.
The groups above that fit this description are the Lingulata
and Obolellida; all others have articulating hinges.
Recently it has been argued that hinge
articulation is not a good character on which to make
brachiopod groups. Thus, we break up the brachiopods
as shown above, following Popov et al. (1993). It should be
noted here that brachiopod phylogeny has been unstable in
recent years, with various authors proposing that brachiopods
are polyphyletic -- that is, that different brachiopod groups
evolved separately from phoronid-like ancestors.